Plasma may be used in various processes for physically and/or chemically altering a surface of a workpiece. For example, plasma may be used to deposit or spray a layer of material onto a workpiece, to etch or sputter away unwanted material from a workpiece, or to perform ashing or stripping processes on a workpiece. Typically, plasma is generated using a plasma generator, which may include a tube, a coil, and a processing gas source. The tube may be made of a dielectric material, such as quartz or alumina/sapphire, and may be at least partially surrounded by the coil. An inner surface of the tube defines a plasma chamber that is in flow communication with the processing gas source to receive a processing gas. To diffuse the processing gas before injection into the plasma chamber, a gas flow distribution receptacle may be disposed over an inlet thereof.
During operation, the coil is energized to create an electric field within the plasma chamber. As the processing gas flows through the electric field, a portion of the processing gas is ignited and transforms into a plasma, which may include reactive species such as electrons, ions, and reactive radicals. The reactive species flow to the workpiece and, depending on the particular process in which the plasma is used, may deposit onto the workpiece to form a layer or may react with materials on the workpiece to form removable species.
Although the aforementioned system yields high quality plasma, the system may be improved. For example, plasma generation may not reliably occur on a first attempt and hence, repeated attempts may be performed before the processing gas is successfully ignited. In cases in which more than one workpiece is processed with the system, the repeat attempts at ignition may interrupt workpiece production, which may undesirably add time to workpiece processing. Additionally, a relatively large amount of power (e.g., at least 1000 Watts) may be supplied to the coil in order to ignite the processing gas. However, repeated exposure to the high voltages may affect operability of some of the system components that surround and/or are coupled to the coil, such as generators and/or matching network circuits. Hence, the surrounding system components may have reduced useful lives, thereby increasing repair frequency and costs.
Accordingly, it is desirable to have a plasma generator system that has improved plasma generation capabilities over conventional systems. It is also desirable for the plasma generator system to have reduced downtime between plasma generation processes. Additionally, it is desirable for the plasma generator system to generate plasma, while reducing exposure of surrounding system components to high amounts of power, as compared to conventional systems. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.